1. Field of the Invention
The present invention relates generally to brake monitoring systems and arrangements for use in connection with an air brake arrangement, and in particular to a brake monitoring system and an air brake arrangement for a train, railcar, railway vehicle, and similar vehicles, and preferably an electronically-controlled pneumatic air brake arrangement for a railway vehicle.
2. Description of the Related Art
As is known, braking systems and arrangements are required for slowing and stopping vehicles, such as cars, trucks, trains, railcars, railway vehicles, and the like. With specific respect to trains and other railway vehicles, the braking system is normally in the form of a pneumatically-driven arrangement (or “air brake arrangement”) having mechanisms and components that interact with each railcar. A known air brake arrangement BA is illustrated in schematic form in FIG. 1.
With reference to FIG. 1, the operator of a train TR also has control over the braking arrangement BA through the use of an operator control valve CV. Through the movement of a handle associated with the control valve CV, the operator can adjust the amount of braking to be applied in the air brake arrangement BA. The higher the braking force selected, the faster the braking arrangement BA will attempt to slow and stop the train TR. Alternatively, and as discussed in more detail hereinafter, the air brake arrangement BA for each railcar may also be controlled by the operator from an on-board controller OBC that transmits data signals over a trainline TL (or cable extending between the locomotive and the railcars), which may be referred to as an electronically-controlled pneumatic (ECP) air brake arrangement.
In order to provide the appropriately compressed air to the system, and in certain conventional air brake applications, the air brake arrangement BA also includes a compressor C for providing compressed air to a main reservoir MR, which is in communication with the control valve CV. Further, an equalizing reservoir ER is also in communication with the control valve CV. Whether through the main reservoir MR or the equalizing reservoir ER, compressed air is supplied through the control valve CV to a brake pipe BP that extends along and is associated with each railcar. Each railcar includes an arrangement that allows an auxiliary reservoir AR to be charged with air via a valve V, as well as a braking assembly or unit BU, such as a brake cylinder BC, which is in communication with the valve V. The brake cylinder BC is operable to urge a brake shoe mechanism BS against a surface of the wheel W.
In operation, the brake pipe BP is continually charged to maintain a specific pressure, e.g., 90 psi, and each auxiliary reservoir AR and emergency reservoir ER (which may be combined into a single volume, or main reservoir) are similarly charged from the brake pipe BP. In order to brake the train TR, the operator actuates the control valve CV and removes air from the brake pipe BP, thereby reducing pressure to a lower level, e.g., 80 psi. The valve arrangement V quits charging the auxiliary reservoir AR and transfers air from the auxiliary reservoir AR to the brake cylinder BC. Normally using piston-operable arrangement, the brake cylinder BC urges the brake shoe mechanism BS against the wheel W. As discussed, in conventional, non-ECP air brake systems, the operator may adjust the level of braking using the control valve CV, since the amount of pressure removed from the brake pipe BP results in a specific pressure in the brake cylinder BC, which results in a specific application force of the brake shoe mechanism BS against the wheel W. Alternatively, in the ECP air brake arrangements, the brake commands are electronic over the ECP trainline TL to each railcar.
Using the above-described air brake arrangement BA, the train can be slowed and/or stopped during operation and as it traverses the track. Further, each railcar is typically equipped with a manual parking brake PB for securing each car when parked or stopped, and in order to ensure that the train does not move or shift. Still further, certain railcars may be equipped with a hatch reservoir HR to provide air to a pneumatically-operable hatch or door of the railcar.
In order to provide further control to the air brake arrangement BA, ECP brake arrangements can be used. As discussed, control signals can be transmitted from the on-board controller OBC, typically located in the cabin of the locomotive, to one or more of the railcars over the trainline TL. Each railcar is normally equipped with a local controller LC, which is used to monitor and/or control certain operating parameters in the air brake arrangement BA, such as the air reservoirs and/or the valve arrangement V. In this manner, the operator can broadcast brake commands to the railcars to ensure a smooth, efficient, and effective braking operation. This local controller LC typically includes the appropriate processor and components to monitor and/or control various components of the air brake arrangement BA.
As discussed above, conventional freight cars have manual parking brakes PB, which provide a mechanical locking of brakes, based upon user operation of a wheel to apply force to a chain connected to a brake lever system. Actuation of these manual parking brakes PB causes the brake shoe mechanisms BS to contact the wheel W. Operating rules are established by railroads, which require application of the parking brake PB under a variety of conditions. The most common condition is when “setting a car off” from the train TR, in order to park it in a yard or siding track. However, as referred to above, the manual parking brakes PB are also used to secure a train TR under failure (or emergency) conditions when in mainline operation. For example, these manual parking brakes PB may be used when a train TR failure exists, where the locomotives are no longer able to maintain brake pipe BP pressure. Another such condition exists when a crew needs to secure the train TR and leave the locomotive unmanned. A still further condition arises when the train TR suffers a “break-in-two” event, leaving a group of cars without a locomotive.
The “break-in-two” event and other conditions requiring the stopping of a train TR are addressed through exhausting the brake pipe BP, which will lead to an emergency brake application. Typical air brake systems, even if maintained to AAR standards, can have a brake cylinder leak rate of up to 1 psi per minute, which are considered to be within acceptable leakage rates. This level is normally used to provide a time guideline for train crews to gauge when to manually apply the manual parking brakes PB and secure the train TR. The number of cars that require this parking brake application may vary based on the number of cars in the train consist, as well as the average grade of the track. Crews normally need to apply the manual parking brakes PB within about a half hour after the condition arises, and after the parking brakes PB are applied, the brake cylinder BC can leak to zero, such that the car will be secured.
There exists a need in the industry to reduce the need for the crew to manually apply the parking brakes PB. This is primarily based upon the desire to reduce the risk of injury to the crew involved in such manual field operations. This need is also rising with the trend towards single person-operated trains, with some railroads planning for future unmanned operations. While some potential solutions may involve locking schemes in the brake cylinder BC and powered hand brakes, such arrangements represent complex and costly solutions.